The present invention relates generally to pulling apparatus and more specifically to such pulling apparatus as is designed for use in repair of collision damage to motor vehicles such as straightening of frame panels or the like.
Various types of pulling apparatus have long been in use in connection with straightening of motor vehicle frames and other various body components. Generally, such apparatus comprises one or more vertically elongated support members having a plurality of longitudinally spaced holes provided therein. A shaft may be inserted through such holes to variably position guide means such as a pulley through which a chain may be lead and one end thereof attached to an appropriate portion of a motor vehicle. Tensioning means generally in the form of a hydraulically actuated piston is operatively associated with the apparatus and arranged so that the other end of the chain may be connected thereto so as to exert a pulling force upon the motor vehicle. While the plurality of openings afford some degree of height adjustment for the upper pulley, the number or spacing thereof is limited by the necessity for substantial strength in the vertical members without excessively increasing the size thereof and resulting cost and weight. Weight reduction is important in that the pulling apparatus will generally be stored in a remote location thus necessitating it be maneuvered into position for each pulling operation. Further, a particular workpiece may require the apparatus to be repositioned several times to properly effect the repair thereof. Thus, any unnecessary weight will impair the maneuverability thereof.
Typically, the vertical member is supported upon a base by a plurality substantially identical equal length upwardly inclined braces extending therebetween. As each of these braces is substantially identical the size and associated strength thereof is dictated by those carrying the heaviest load. This may result in oversizing the other braces thereby unnecessarily increasing manufacturing costs as well as the weight thereof which may also make maneuvering of the apparatus into position more difficult.
Accordingly, the present invention provides a unique pulling apparatus comprising a pair of vertical members which are each supported in a substantially parallel spaced relationship by a pair of unequal length depending diverging support members arranged so as to distribute the loading thereon in such a manner as to maximize the support thus provided while minimizing the size and weight of such members. The use of minimal size support members without reducing the overall ruggedness and rigidity of the pulling apparatus is important in reducing the cost thereof as well as weight reduction so as to facilitate handling of the apparatus during use. Also, the present invention provides inwardly opening opposed channels on the vertical members within which an upper pulley is movably supported preferably by a pair of chains depending from load holding assembly supported on top of the vertical members. The suspension chains and load holding assembly cooperate with the channels to enable each link of the suspension chains to provide a different working height for the pulley. This feature thus enables greater flexibility in controlling the angle or direction of pulling relative to the workpiece which control is critical to proper, efficient, and effective repair of such motor vehicles or the like.
Additional advantages and features of the present invention will become apparent from the subsequent description and the appended claims taken in conjunction with the accompanying drawings.